rubidium

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Symbol:

Rb

Atomic Number:

37

Relative Atomic Mass:

85.4678 g mol^-1

Natural Abundance in Lithosphere, hydrosphere and atmosphere:

0.03% (mass fraction)

Electron Configuration:

[Kr]5s

Oxidation States:

I

Atomic Radius:

247.5pm

Covalent Radius:

216pm

Ionic Radius:

152pm (for +1 oxidation state, 6 coordinate)

161pm (for +1 oxidation state, 8 coordinate)

Melting Point:

38.9°C

Density:

1.53 g cm^-3 (at 20°C)

First Ionisation Energy:

4.177 eV

Reduction Potential:

-2.98V

for Rb⁺ + e^- a Rb_(s)

Electronegativity (Allred and Rochow):

0.9

Number of Natural Isotopes:

2

Mass Number of the Most Abundant Isotopes:

85 g mol^-1 a 72.2% abundance

87 g mol^-1 a 27.8% abundance